Circuit module having dual-mode wideband power amplifier architecture

ABSTRACT

A circuit module includes a power amplifier, a switch, and a bypass capacitor. The power amplifier has a signal input node coupled to an input signal, a signal output node to generate an output signal, and a power input node coupled to a supply output signal of a supply modulator. The switch is coupled between the power input node of the power amplifier and the bypass capacitor. The bypass capacitor is an equivalently removable bypass capacitor coupled between the switch and a ground level.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of U.S. provisional application Ser.No. 62/544,109 filed on Aug. 11, 2017, which is entirely incorporatedherein by reference.

BACKGROUND

The invention relates to power amplifier architecture, and moreparticular to a circuit module having such power amplifier architecture.

Generally speaking, a conventional scheme is to adopt a power amplifierwith a dynamically adjusted power supply to improve the efficiency ofthe power amplifier. However, as the operating signal bandwidthincreases, the efficiency of a supply modulator, used for providing asupply power for the power amplifier, inevitably drops, and thus theoverall system efficiency is degraded.

Further, another conventional scheme may adopt a power amplifier with afixed power supply to improve the system linearity. However, to improvethe system linearity, the fixed power supply may be increased, and thusthis will sacrifice the system efficiency.

SUMMARY

Therefore one of the objectives of the invention is to provide a circuitmodule having dual-mode wideband power amplifier architecture, to solvethe above-mentioned problems.

According to embodiments of the invention, a circuit module isdisclosed. The circuit module includes a power amplifier, a switch, anda bypass capacitor. The power amplifier has a signal input node coupledto an input signal, a signal output node to generate an output signal,and a power input node coupled to a supply output signal of a supplymodulator. The switch is coupled between the power input node of thepower amplifier and the bypass capacitor. The bypass capacitor is anequivalently removable bypass capacitor coupled between the switch and aground level.

According to embodiments of the invention, a method of operating a poweramplifier circuit module is disclosed. The power amplifier circuitmodule includes a power amplifier having a power input node forreceiving a supply signal from a supply modulator. The method includeselectrically connecting a bypass capacitor to the power input node whenthe power amplifier circuit module operates at a first mode, andelectrically disconnecting the bypass capacitor from the power inputnode when the power amplifier circuit module operates at a second modedifferent from the first mode. The distance from the bypass capacitor tothe power amplifier is shorter than the distance from the bypasscapacitor to the supply modulator.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a circuit module according to a firstembodiment of the invention.

FIG. 2 shows a modification embodiment of circuit module as shown onFIG. 1.

FIG. 3 shows another modification embodiment of circuit module as shownon FIG. 1.

FIG. 4 is a diagram of a circuit module according to a second embodimentof the invention.

FIG. 5 is a diagram showing a modification of the circuit module basedon the embodiment of FIG. 4.

FIG. 6 is a diagram showing a modification of a circuit module accordingto the embodiment of FIG. 4.

FIG. 7 is a diagram showing another modification of a circuit moduleaccording to the embodiment of FIG. 4.

DETAILED DESCRIPTION

The invention aims at providing a solution of dual-mode (hybrid)wideband power amplifier circuit structure/architecture for a widebandsupply modulator which can operate at small/large signal bandwidths, toimprove the efficiency of the whole system as well as the systemlinearity. In some examples of the invention, two modes of operation aresupported, namely a dynamic supply mode (for example, an envelopetracking scheme) and a fixed supply mode (for example, an average powertracking scheme). The selection of the mode to be used in providing thepower supply to the PA is performed by a mode selection signal generatedfrom a mode control module. In dynamic supply mode, the PA power supplyis a time varying signal, which tracks the required signal envelope, inorder to achieve the efficiency benefits. In fixed supply mode, the PApower supply is fixed at a specific voltage requirement in order tosupport the transmitted waveform, in order to achieve the linearitybenefits. In some examples of the invention, the mode selection is basedon signal bandwidth. For small bandwidth, the mode control moduleselects dynamic supply mode and the power amplifier circuit operateswith dynamic power supply. For large bandwidth, the mode control moduleselects fixed supply mode and the power amplifier circuit operates withfixed power supply. This solution employs and places removable bypasscapacitor(s) in the neighborhood of power amplifier(s). The bypasscapacitor(s) in the neighborhood of a power amplifier can be removed(e.g. electrically disconnected from the power amplifier) when the poweramplifier is supplied with a dynamically adjusted power supply (e.g. asupply modulator operates at the small signal bandwidth). This improvesthe system efficiency and is suitable for the small bandwidth supplymodulation. By removing the bypass capacitor(s), the capacitance of thebypass capacitor(s) would not affect the loading of the power amplifiercircuit. Additionally, the bypass capacitor(s) in the neighborhood ofthe power amplifier can exist (e.g. electrically connected to the poweramplifier) and can be seen by the power amplifier when the poweramplifier is supplied with a fixed power supply (e.g. the supplymodulator operates at the large signal bandwidth). The removable bypasscapacitor(s) in this mode can be used to increase the purity of thevoltage of the fixed power supply, to keep the voltage of the fixedpower supply constant, and/or to filter the noise, thereby improving thesystem linearity as well as the system efficiency. This is because ifthe bypass capacitor(s) is not electrically connected, the voltage ofthe fixed power supply needs to be increased in order to improve thelinearity, and increasing the voltage of the fixed power supply resultsinefficiency sacrifice. By providing bypass capacitor(s) under fixedsupply mode or large bandwidth condition and removing the bypasscapacitor(s) under dynamic supply mode or small bandwidth condition, theefficiency and linearity of the whole system are improved. In someexamples, the bypass capacitor(s) are preferred to be placed or disposedcloser to the power amplifier than to the supply modulator for ripplesuppression and/or interference suppression.

FIG. 1 is a block diagram of a circuit module 100 according to a firstembodiment of the invention. The circuit module 100 comprises a poweramplifier PA1, a switch SW1, and at least one bypass capacitor Cb. Thecircuit module 100 for example is a radio frequency front end circuitmodule.

The power amplifier PA1 has a signal input node coupled to an inputsignal SIN, a signal output node to generate an output signal SOUT, anda power input node coupled to a supply output signal VSP of a supplymodulator 105. The supply modulator 105 is configured to convert asystem power into the supply output signal VSP for the power amplifierPA1. The supply modulator 105 may include a DC-DC converter, an envelopetracking modulator, or a pulse width modulator.

The switch SW1 is coupled between the power input node of the poweramplifier PA1 and the bypass capacitor Cb which is coupled between theswitch SW1 and a ground level. The switch SW1 for example may beimplemented by using a MOS transistor (but not limited).

The circuit module 100 is a dual-mode wideband circuit module in whichthe power amplifier PA1 can be regarded as a dual-mode wideband poweramplifier. The circuit module 100 has two modes and operates underdifferent modes for different small/larger signal bandwidths, i.e. ahybrid circuit module. For example, the circuit module 100 operatesunder a first mode when the supply modulator 105 operates at a firstsignal bandwidth such as a small signal bandwidth. In the first mode,the switch SW1 is turned off to become open when the supply modulator105 operates at the small signal bandwidth, and the power input node ofpower amplifier PA1 is electrically disconnected from the bypasscapacitor Cb. The bypass capacitor Cb is not seen by the power amplifierPA1; equivalently, the bypass capacitor Cb in this mode is removed. Thesupply modulator 105 is arranged to track the envelope of the signaloutputted by or inputted to the power amplifier to modulate and providethe supply output signal VSP for the power amplifier PA1, and the poweramplifier PA1 is used as an envelope tracking amplifier. This can beachieved by providing the supply modulator 105 with the information ofenvelope of the transmitted signal in either digital form or analogform. Moreover, since the switch SW1 is turned off, the capacitorloading can be reduced.

The circuit module 100 operates under a second mode when the supplymodulator 105 operates at a second signal bandwidth such as a largesignal bandwidth larger than the first signal bandwidth. In the secondmode, the switch SW1 is turned on to become closed when the supplymodulator 105 operates at the larger signal bandwidth, and the powerinput node of power amplifier PA1 is electrically connected to thebypass capacitor Cb. The bypass capacitor Cb is seen by the poweramplifier PA1 in this mode. The power supply signal VSP is fixed at theminimum voltage requirement of the power amplifier (e.g. fixed at alevel corresponding to the maximum of the transmitted envelope waveformplus a margin) in order to support the transmitted waveform, for examplefor a time period between power level updates. The power amplifier PA1is used as an average power tracking amplifier. Since the switch SW1 isturned on and the bypass capacitor Cb is seen, the supply output signalVSP for the power amplifier PA1 can be regulated. In addition, theswitch SW1 is controlled by a mode selection signal generated from amode control module (not shown in FIG. 1). In some examples, the modecontrol module is included in a baseband processing module or controlledby the baseband processing module.

In addition, in this embodiment, the circuit module 100 is implementedwithin an integrated circuit chip. That is, the power amplifier PA1,switch SW1, and bypass capacitor Cb are encapsulated or packaged withinthe integrated circuit chip. As shown on FIG. 1, the dotted lineindicates the chip boundary of such integrated circuit chip.

In addition, when the switch SW1 is turned on to be closed, the circuitdistance from the bypass capacitor Cb to the power amplifier PA1 isshorter than the circuit distance from the bypass capacitor Cb to thesupply modulator 105. That is, the bypass capacitor Cb is closer to thepower amplifier PA1 than the supply modulator 105. In this way, theperformance of ripple suppression or interference (e.g. adjacent channelleakage ratio) suppression can be further improved.

Further, in other implementation, the power amplifier PA1 and switch SW1may be implemented within the integrated circuit chip, and the bypasscapacitor Cb may be configured to be externally connected to theintegrated circuit chip. That is, the capacitor Cb is not encapsulatedwithin such integrated circuit chip. FIG. 2 shows a modificationembodiment of circuit module 100 as shown on FIG. 1. As shown on FIG. 2,the dotted line indicates the chip boundary of such integrated circuitchip, and the bypass capacitor Cb is not included within the chipboundary. It is noted that in this embodiment the bypass capacitor Cb iscloser to the power amplifier PA1 than the supply modulator 105 when theswitch SW1 is turned on. Similarly, the performance of ripplesuppression or interference (e.g. adjacent channel leakage ratio)suppression can be further improved.

Further, in other implementation, the power amplifier PA1 is implementedwithin the integrated circuit chip, and the switch SW1 and bypasscapacitor Cb can be configured to be externally connected to theintegrated circuit chip. That is, the bypass capacitor Cb and switch SW1are not encapsulated within such integrated circuit chip. FIG. 3 showsanother modification embodiment of circuit module 100 as shown onFIG. 1. As shown on FIG. 3, the dotted line indicates the chip boundaryof such integrated circuit chip, and the switch SW1 and bypass capacitorCb are not included within the chip boundary. The bypass capacitor Cb iscloser to the power amplifier PA1 than the supply modulator 105 when theswitch SW1 is turned on. Similarly, the performance of ripplesuppression or interference (e.g. adjacent channel leakage ratio)suppression can be further improved.

In other embodiments, the circuit module may be formed by multiple-stagepower amplifiers. FIG. 4 is a diagram of a circuit module 400 accordingto a second embodiment of the invention. As shown on FIG. 4, the circuitmodule 400 comprises multiple-stage power amplifiers connected in seriesat plurality of stages. For example, the circuit module 400 comprisesthe power amplifier PA1 at the output stage and at least one poweramplifier PA2 at the input stage. The power amplifiers PA1 and PA2 areencapsulated within an integrated circuit chip, and the dotted line onFIG. 4 indicates the chip boundary of such integrated circuit chip.

The signal input node of power amplifier PA2 is coupled to the inputsignal SIN, and its output node is coupled to the signal input node ofpower amplifier PA1. The power input node of power amplifier PA2 iscoupled to the supply output signal VSP of supply modulator 105 via aport P2 of the integrated circuit chip. An internal capacitor C1 isencapsulated within the integrated circuit chip and is placed andcoupled between the power input node of power amplifier PA2 and theground level. An external capacitor C2 is externally coupled to the portP2 of such integrated circuit chip and is placed and coupled between theport P2 and the ground level. For example, the internal capacitor C1 andexternal capacitor C2 may be configured to be closer to the power inputnode of power amplifier PA2 and port P2, respectively.

The signal input node of power amplifier PA1 is coupled to the outputnode of power amplifier PA2, and the power amplifier PA1 generates theoutput signal SOUT at its signal output node. The power input node ofpower amplifier PA1 is coupled to the supply output signal VSP of supplymodulator 105 via a port P1 of the integrated circuit chip. An internalcapacitor C1 is encapsulated within the integrated circuit chip and isplaced and coupled between the power input node of power amplifier PA1and the ground level. An external capacitor C2 is externally coupled tothe port P1 of such integrated circuit chip and is placed and coupledbetween the port P1 and the ground level. For example, the internalcapacitor C1 and external capacitor C2 may be configured to be closer tothe power input node of power amplifier PA1 and port P1, respectively.The internal capacitors C1 are used as voltage stabilizer elements forcircuit element(s) within the integrated circuit chip, and the externalcapacitors C2 are used as voltage stabilizer elements for circuitelement(s) externally connected to the integrated circuit chip; thecapacitors C1 and C2 may be optional.

The supply modulator 105 is configured to convert a system power intothe supply output signal VSP for the power amplifiers PA1 and PA2. Thesupply modulator 105 may include a DC-DC converter, an envelope trackingmodulator, or a pulse width modulator.

The bypass capacitor Cb is coupled to the power input node of poweramplifier PA1 via the switch SW1 and a port Pb of the integrated circuitchip. The bypass capacitor Cb is closer to the port Pb.

Similarly, the circuit module 400 is a dual-mode wideband circuit modulein which the power amplifiers PA1 and PA2 can be regarded as dual-modewideband power amplifiers. The circuit module 400 has two modes andoperates under different modes for different signal bandwidths, i.e. ahybrid circuit module. For example, the circuit module 400 operatesunder a first mode when the supply modulator 105 operates at a firstsignal bandwidth such as a small signal bandwidth. In the first mode,the switch SW1 is turned off to become open when the supply modulator105 operates at the small signal bandwidth, and the power input node ofpower amplifier PA1 is electrically disconnected from the bypasscapacitor Cb. Also, the power input node of power amplifier PA2 at theinput stage is electrically disconnected from the bypass capacitor Cb.In this situation, the bypass capacitor Cb is not seen by the poweramplifiers PA1 and PA2. Equivalently, for power amplifiers PA1 and PA2,the bypass capacitor Cb is removed. The supply modulator 105 is arrangedto track the envelope of the signal outputted by or inputted to thepower amplifiers to modulate and provide the supply output signal VSPfor the power amplifiers PA1 and PA2, and the power amplifiers PA1 andPA2 are used as envelope tracking amplifiers. This can be achieved byproviding the supply modulator 105 with the information of envelope ofthe transmitted signal in either digital form or analog form. Moreover,since the switch SW1 is turned off, the capacitor loading can bereduced.

Additionally, the circuit module 400 operates under a second mode whenthe supply modulator 105 operates at a second signal bandwidth such as alarge signal bandwidth larger than the first signal bandwidth. In thesecond mode, the switch SW1 is turned on to become closed when thesupply modulator 105 operates at the larger signal bandwidth, and thepower input node of power amplifier PA1 is electrically connected to thebypass capacitor Cb. Also, the power input node of power amplifier PA2is electrically connected to the bypass capacitor Cb. The bypasscapacitor Cb is seen by the power amplifiers PA1 and PA2. The circuitdistance from the power input node of power amplifier PA2 to the bypasscapacitor Cb may be longer than that from the power input node of poweramplifier PA1 to the bypass capacitor Cb. The bypass capacitor Cb isstill closer to the power amplifiers PA1 and PA2 than the supplymodulator 105. The power supply signal VSP is fixed at the minimumvoltage requirement of the power amplifiers (e.g. fixed at a levelcorresponding to the maximum of the transmitted envelope waveform plus amargin) in order to support the transmitted waveform. The poweramplifiers PA1 and PA2 are used as average power tracking amplifiers.Since the switch SW1 is turned on and the bypass capacitor Cb is seen,the supply output signal VSP for the power amplifiers PA1 and PA2 can beregulated.

For example (but not limited), if the supply modulator 105 is configuredto operate under a large signal bandwidth from zero to the maximumfrequency, then the circuit module 400 operates under the second mode,and the switch SW1 is turned on to become closed. The power amplifiersPA1 and PA2 are used as average power tracking amplifiers. Additionally,if the supply modulator 105 is configured to operate under a smallsignal bandwidth from zero to a threshold frequency lower than themaximum frequency, then the circuit module 400 operates under the firstmode, and the switch SW1 is turned off to become open. The poweramplifiers PA1 and PA2 are used as envelope tracking amplifiers. In someexamples, the threshold frequency corresponds to the bandwidth that thesupply modulator 105 can operate. In some examples, the thresholdfrequency is around 60 MHz.

Further, for implementation, the capacitance of bypass capacitor Cb maybe configured to be one thousand times more than the capacitances ofcapacitors C1 and C2. For example, the capacitance of bypass capacitorCb may be configured as a value of the order of μF, and the capacitancesof capacitors C1 and C2 are configured as the values of the order of pF.For instance, the capacitances of capacitors C1 and C2 may be designedas 10-100 pF (but not limited).

FIG. 5 is a diagram showing a modification 500 of the circuit modulebased on the embodiment of FIG. 4. As shown by FIG. 5, the power inputnode of power amplifier PA2 is coupled to another distinct bypasscapacitor Cb′ via the switch SW2 and the port Pb′ of integrated circuitchip. Identically, the power input node of power amplifier PA2 iscoupled to the supply output signal VSP of supply modulator 105 via theport P2 of the integrated circuit chip. Identically, the circuit module500 is a dual-mode wideband circuit module in which the power amplifiersPA1 and PA2 can be regarded as dual-mode wideband power amplifiers. Thecircuit module 500 has two modes and operates under different modes fordifferent signal bandwidths, i.e. a hybrid circuit module. For example,the circuit module 500 operates under a first mode when the supplymodulator 105 operates at a first signal bandwidth such as a smallsignal bandwidth. In the first mode, the switches SW1 and SW2 are turnedoff to become open respectively when the supply modulator 105 operatesat the small signal bandwidth, and the power input nodes of poweramplifiers PA1 and PA2 are electrically disconnected from the bypasscapacitors Cb and Cb′, respectively. The bypass capacitors Cb and Cb′are not seen by the power amplifiers PA1 and PA2. For power amplifiersPA1 and PA2, the bypass capacitors Cb and Cb′ are removed in thissituation. The supply modulator 105 is arranged to track the envelope ofthe signal provided by or inputted to the power amplifiers to modulateand provide the supply output signal VSP for the power amplifiers PA1and PA2, and the power amplifiers PA1 and PA2 are used as envelopetracking amplifiers. This can be achieved by providing the supplymodulator 105 with the information of envelope of the transmitted signalin either digital form or analog form. Moreover, since the switches SW1and SW2 are turned off, the capacitor loading can be reduced.

Additionally, the circuit module 500 operates under a second mode whenthe supply modulator 105 operates at a second signal bandwidth such as alarge signal bandwidth larger than the first signal bandwidth. In thesecond mode, the switches SW1 and SW2 are turned on to become closedrespectively when the supply modulator 105 operates at the larger signalbandwidth, and the power input nodes of power amplifiers PA1 and PA2 areelectrically connected to the bypass capacitors Cb and Cb′,respectively. The bypass capacitors Cb and Cb′ are seen by the poweramplifiers PA1 and PA2. The circuit distance from bypass capacitor Cb topower amplifier PA1 is shorter than that from bypass capacitor Cb tosupply modulator 105, and also the circuit distance from bypasscapacitor Cb′ to power amplifier PA2 is shorter than that from bypasscapacitor Cb′ to supply modulator 105. That is, the bypass capacitors Cband Cb′ are closer to the power amplifiers PA1 and PA2 than the supplymodulator 105. In this mode, the power supply signal VSP is fixed at theminimum voltage requirement of the power amplifier (e.g. fixed at alevel corresponding to the maximum of the transmitted envelope waveformplus a margin) in order to support the transmitted waveform. The poweramplifiers PA1 and PA2 are used as average power tracking amplifiers.Since the switches SW1 and SW2 are turned on and the bypass capacitorsCb and Cb′ are seen, the supply output signal VSP for the poweramplifiers PA1 and PA2 can be regulated.

FIG. 6 is a diagram showing a modification 600 of a circuit moduleaccording to the embodiment of FIG. 4. As shown on FIG. 6, the circuitmodule 600 comprises multiple power amplifiers connected in series atplurality of stages. For example, the circuit module 600 comprises thepower amplifier PA1 at the output stage and the power amplifier PA2 atthe input stage. The power amplifiers PA1 and PA2 are encapsulated orpackaged within an integrated circuit chip, and the dotted line on FIG.6 indicates the chip boundary of such integrated circuit chip. Thebypass capacitor Cb is coupled to the power input node of poweramplifier PA1 via the switch SW1 and the port Pb of the integratedcircuit chip. In addition, the power input node of power amplifier PA2is coupled to the power input node of power amplifier PA1 and the supplyoutput signal VSP via the node P1.

Identically, the circuit module 600 is a dual-mode wideband circuitmodule in which the power amplifiers PA1 and PA2 can be regarded asdual-mode wideband power amplifiers. The circuit module 600 has twomodes and operates under different modes for different signalbandwidths, i.e. a hybrid circuit module. For example, the circuitmodule 600 operates under a first mode when the supply modulator 105operates at a first signal bandwidth such as a small signal bandwidth.In the first mode, the switch SW1 is turned off to become open when thesupply modulator 105 operates at the small signal bandwidth, and thepower input nodes of power amplifiers PA1 and PA2 are electricallydisconnected from the bypass capacitor Cb, respectively. The bypasscapacitor Cb is not seen by the power amplifiers PA1 and PA2. The bypasscapacitor Cb is equivalently removed. In this mode, the supply modulator105 is arranged to track the envelope of the signal provided by orinputted to the power amplifiers to modulate and provide the supplyoutput signal VSP for the power amplifiers PA1 and PA2, and the poweramplifiers PA1 and PA2 are used as envelope tracking amplifiers. Thiscan be achieved by providing the supply modulator 105 with theinformation of envelope of the transmitted signal in either digital formor analog form. Moreover, since the switch SW1 is turned off, thecapacitor loading can be reduced.

Additionally, the circuit module 600 operates under a second mode whenthe supply modulator 105 operates at a second signal bandwidth such as alarge signal bandwidth larger than the first signal bandwidth. In thesecond mode, the switch SW1 is turned on to become closed when thesupply modulator 105 operates at the larger signal bandwidth, and thepower input nodes of power amplifiers PA1 and PA2 are electricallyconnected to the bypass capacitor Cb respectively. The bypass capacitorCb is seen by the power amplifiers PA1 and PA2. The bypass capacitor Cbis closer to the power amplifiers PA1 and PA2 than the supply modulator105. In this mode, the power supply signal VSP is fixed at the minimumvoltage requirement of the power amplifiers (e.g. fixed at a levelcorresponding to the maximum of the transmitted envelope waveform plus amargin) in order to support the transmitted waveform. The poweramplifiers PA1 and PA2 are used as average power tracking amplifiers.Since the switch SW1 is turned on and the bypass capacitor Cb is seen,the supply output signal VSP for the power amplifiers PA1 and PA2 can beregulated. Other functions and operations are similar and not detailedfor brevity.

In other embodiments, the power amplifier PA2 at the input stage may bean average power tracking amplifier instead of a hybrid power amplifierso as to reduce the implementation complexity. FIG. 7 is a diagramshowing another modification 700 of a circuit module according to theembodiment of FIG. 4. As shown on FIG. 7, the circuit module 700comprises multiple power amplifiers connected in series at plurality ofstages. For example, the circuit module 700 comprises the poweramplifier PA1 at the output stage and the power amplifier PA2 at theinput stage. The power amplifiers PA1 and PA2 are encapsulated orpackaged within an integrated circuit chip, and the dotted line on FIG.7 indicates the chip boundary of such integrated circuit chip. Thebypass capacitor Cb is coupled to the power input node of poweramplifier PA1 via the switch SW1 and the port Pb of the integratedcircuit chip. The power input node of power amplifier PA1 is coupled toa supply output signal VSP1 of supply modulation 705, and the powerinput node of power amplifier PA2 is coupled to another supply outputsignal VSP2 of supply modulator 705 via the port P2. The supplymodulator 705 is arranged to provide the distinct supply output signalsVSP1 and VSP2 which can be identical or different.

The circuit module 700 is a dual-mode wideband circuit module in whichthe power amplifier PA1 is regarded as dual-mode wideband poweramplifier and the power amplifier PA2 is regarded as an average powertracking amplifier. The circuit module 700 has two modes and operatesunder different modes for different signal bandwidths, i.e. a hybridcircuit module. For example, the circuit module 700 operates under afirst mode when the supply modulator 705 operates at a first signalbandwidth such as a small signal bandwidth. In the first mode, theswitch SW1 is turned off to become open when the supply modulator 705operates at the small signal bandwidth, and the power input node ofpower amplifier PA1 is electrically disconnected from the bypasscapacitor Cb. The bypass capacitor Cb is not seen by the power amplifierPA1, and equivalently the bypass capacitor Cb is removed for the poweramplifier PA1. The power input node of power amplifier PA2 iselectrically connected to the supply output signal VSP2 via the port P2of the integrated circuit chip. In this mode, the supply modulator 705is arranged to track the envelope of the signal provided by or inputtedto the power amplifiers to modulate and provide the supply output signalVSP1 for the power amplifier PA1, and the power amplifier PA1 is used asan envelope tracking amplifier. The switch SW1 is turned off, and thecapacitor loading can be reduced. In addition, the supply modulator 705is arranged to generate the supply output signal VSP2 for the poweramplifier PA2 based on the minimum voltage requirement of the poweramplifier (e.g. a level corresponding to the maximum of the transmittedenvelope waveform plus a margin), and the power amplifier PA2 is used asan average power tracking amplifier. The supply output signal VSP1 inthis mode is different from the supply output signal VSP2.

Additionally, the circuit module 700 operates under a second mode whenthe supply modulator 705 operates at a second signal bandwidth such as alarge signal bandwidth larger than the first signal bandwidth. In thesecond mode, the switch SW1 is turned on to become closed when thesupply modulator 705 operates at the larger signal bandwidth, and thepower input node of power amplifier PA1 is electrically connected to thebypass capacitor Cb. The bypass capacitor Cb in this situation is seenby the power amplifier PA1. The bypass capacitor is closer to the poweramplifier PA1 than the supply modulator 705. In this mode, the supplymodulator 705 is arranged to generate the supply output signal VSP1 forthe power amplifier PA1 based on the minimum voltage requirement of thepower amplifier (e.g. a level corresponding to the maximum of thetransmitted envelope waveform plus a margin) in order to support thetransmitted waveform, and the power amplifier PA1 is used as an averagepower tracking amplifier. The supply output signal VSP1 in this mode maybe different from or equal to the supply output signal VSP2. Since theswitch SW1 is turned on and the bypass capacitor Cb is seen, the supplyoutput signal VSP1 for the power amplifier PA1 can be regulated. Otherfunctions and operations are similar and not detailed for brevity.

Although the switch SW1 is shown inside the chip boundary and the bypasscapacitors Cb and Cb′ are shown outside the chip boundary in FIG. 4-FIG.7, it is not meant to be a limitation. The power amplifier circuitmodules 400-700 can be modified in similar ways shown in FIG. 1-FIG. 3.That is, the switch SW1 can be encapsulated or packaged within theintegrated circuit chip or externally coupled to the integrated circuitchip (e.g. not encapsulated within such integrated circuit chip). Thebypass capacitors Cb and Cb′ can be encapsulated or packaged within theintegrated circuit chip or externally coupled to the integrated circuitchip (e.g. not encapsulated within such integrated circuit chip). Thecircuit modules 400-700 may have two or more stages of power amplifiers.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A circuit module, comprising: a first poweramplifier, having a signal input node coupled to an input signal, asignal output node to generate an output signal, and a power input nodecoupled to a supply output signal of a supply modulator; a first switch,externally coupled to the first power amplifier, coupled between thepower input node of the first power amplifier and a first bypasscapacitor; and the first bypass capacitor, coupled between the firstswitch and a ground level; wherein a distance from the first bypasscapacitor to the first power amplifier is shorter than a distance fromthe first bypass capacitor to the supply modulator.
 2. The circuitmodule of claim 1, wherein the first switch is turned off when thesupply modulator operates at a first signal bandwidth, and is turned onwhen the supply modulator operates at a second signal bandwidth which islarger than the first signal bandwidth.
 3. The circuit module of claim1, wherein the circuit module is implemented within an integratedcircuit.
 4. The circuit module of claim 1, wherein the first poweramplifier and the first switch are implemented within an integratedcircuit, and the first bypass capacitor is externally coupled to theintegrated circuit.
 5. The circuit module of claim 1, wherein the firstpower amplifier is implemented within an integrated circuit, and thefirst switch and the first bypass capacitor are externally coupled tothe integrated circuit.
 6. The circuit module of claim 1, furthercomprising: at least one second power amplifier, having a signal inputnode to receive the input signal, a signal output node coupled to thesignal input node of the first power amplifier, and a power input nodeto receive a supply output signal of the supply modulator; a secondswitch, coupled between the power input node of the at least one secondpower amplifier and a second bypass capacitor; and the second bypasscapacitor, coupled between the second switch and the ground level. 7.The circuit module of claim 6, wherein the first switch and the secondswitch are turned off when the supply modulator operates at a firstsignal bandwidth, and are turned on when the supply modulator operatesat a second signal bandwidth which is larger than the first signalbandwidth.
 8. The circuit module of claim 1, further comprising: atleast one second power amplifier, having a signal input node to receivethe input signal, a signal output node coupled to the signal input nodeof the first power amplifier, and a power input node to receive a supplyoutput signal of the supply modulator; wherein the first switch isturned off when the supply modulator operates at a first signalbandwidth, and is turned on when the supply modulator operates at asecond signal bandwidth which is larger than the first signal bandwidth.9. The circuit module of claim 8, wherein the first power amplifier, theat least one second power amplifier, and the first switch are packagedwithin an integrated circuit; the power input node of the first poweramplifier is coupled to the supply output signal via a first port of theintegrated circuit; and, the power input node of the at least one secondpower amplifier is coupled to the supply output signal via a second portof the integrated circuit.
 10. The circuit module of claim 1, furthercomprising: at least one second power amplifier, having a signal inputnode to receive the input signal, a signal output node coupled to thesignal input node of the first power amplifier, and a power input nodeto receive a supply output signal of the supply modulator; wherein thepower input node of the at least one second power amplifier is coupledto the power input node of the first power amplifier and is coupled tothe supply output signal.
 11. The circuit module of claim 10, whereinthe first switch is turned off when the supply modulator operates at afirst signal bandwidth, and is turned on when the supply modulatoroperates at a second signal bandwidth which is larger than the firstsignal bandwidth.
 12. The circuit module of claim 1, further comprising:at least one second power amplifier, having a signal input node toreceive the input signal, a signal output node coupled to the signalinput node of the first power amplifier, and a power input node toreceive another supply output signal of the supply modulator; whereinthe another supply output signal is a fixed power supply signal; thefirst switch is turned off when the supply modulator operates at a firstsignal bandwidth to provide the supply output signal with a dynamicallyadjusted supply voltage; and, the first switch is turned on when thesupply modulator operates at a second signal bandwidth which is largerthan the first signal bandwidth to provide the supply output signal witha fixed supply voltage.
 13. The circuit module of claim 6, wherein adistance from the second bypass capacitor to the second power amplifieris shorter than a distance from the second bypass capacitor to thesupply modulator.
 14. The circuit module of claim 1, further comprisinga voltage stabilizer element coupled to the power input node of thefirst power amplifier, wherein capacitance of the first bypass capacitoris configured to be at least one thousand times more than capacitance ofthe voltage stabilizer element.
 15. A method of operating a poweramplifier circuit module comprising a power amplifier having a powerinput node for receiving a supply signal from a supply modulator, themethod comprising: electrically connecting a bypass capacitor to thepower input node when the power amplifier circuit module operates at afirst mode; and electrically disconnecting the bypass capacitor from thepower input node when the power amplifier circuit module operates at asecond mode different from the first mode; wherein a distance from thebypass capacitor to the power amplifier is shorter than a distance fromthe bypass capacitor to the supply modulator; the electricallyconnecting step and the electrically disconnecting step are performed bya switch which is externally coupled to the power amplifier and iscoupled between the power input node of the power amplifier and thebypass capacitor.
 16. The method of claim 15, wherein the first mode isa fixed supply mode, and the second mode is a dynamic supply mode. 17.The method of claim 15, wherein the first mode is operated with a firstbandwidth, and the second mode is operated with a second bandwidthsmaller than the first bandwidth.